


Mycroft and the Dementors

by supermusicmad



Category: Harry Potter - J. K. Rowling, Sherlock (TV), Sherlock Holmes & Related Fandoms
Genre: Angst, Crossover, Dementors (Harry Potter) - Freeform, Family, Gen, Mention of Child Abuse, mention of drug use
Language: English
Status: Completed
Published: 2013-08-14
Updated: 2013-08-14
Packaged: 2017-12-23 12:42:11
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,578
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/926554
Author URL: https://archiveofourown.org/users/supermusicmad/pseuds/supermusicmad
Summary: <blockquote class="userstuff">
              <p>What does Mycroft see when he and Sherlock are faced with Dementors?</p>
            </blockquote>





	Mycroft and the Dementors

**Author's Note:**

> Written for a prompt on the meme. See if you can spot the line shamelessly pinched from book canon. Also, could not think of a good title. Sorry.

Mycroft is not one for superstition. He, like his brother, does not believe in anything supernatural. Anything that cannot be measured, quantified and explained does not exist. His world is big enough; no ghosts need apply.

There comes a point, however, when the chill pervades too deeply into him to be ascribed purely to the weather.

Mycroft steals a glance at his brother. Sherlock shows no signs of feeling such coldness, except to draw his coat a little more tightly around himself. It is freezing and foggy and Sherlock should not even need his coat and scarf in early July, but the weather is unseasonably bitter. If Sherlock were to walk just a few paces ahead, Mycroft would lose sight of him completely in the fog.

Suddenly Sherlock breaks his step, his whole body stiffening as he senses something just outside his perception. He looks at Mycroft, and for a second their faces hold identical flashes of fear.

“You feel it too, don’t you?” Mycroft says.

Suddenly the fog crashes down on them, obscuring all vision, swirling around them menacingly. Mycroft cannot even see his own hand as he holds it in front of his face, yet alone his brother beside him on the path.

“Mycroft!” Sherlock’s voice could be coming from anywhere; in just a second Mycroft has lost his sense of direction. “Mycroft, where are you?"

Mycroft cannot find the voice to deliver his usual snide comment on either the entirely useless question or the hint of fear in his brother’s voice. Mycroft feels a similar fear, a nameless foreboding that threatens to overwhelm him. The cold is seeping still deeper into him now, beyond just a physical coldness; it is somehow in his _mind_ , smothering his thoughts, in his very _soul_...

“No!” he hears Sherlock shout frantically, followed by several weaker, despondent whimpers of “No... Please, no...”

Mycroft is not aware of falling, but he is suddenly on his knees, groping sightlessly around him for something to support him. He has never felt so wretched in his life, he wants nothing more that to just curl up where he is and close his eyes, but he knows he can’t, not when Sherlock is somewhere just beyond his reach, scared and alone. Something is coming for them through the mist, he is certain of it, and he has to protect his baby brother. Has to protect him... just as he’s always done...

A shape swirls in front of his eyes, and resolves itself into a man, with his back to Mycroft and a stiff leather belt in one hand. He is beating something – or someone – with it mercilessly, grunting with each strike.

A child is crying. Mycroft recognises the cry.

“Stop!” he yells, though his throat seems to be constricting in the cold. “Father, please... Stop it!”

The man is his father, and the cringing, crying boy at his feet is a seven-year-old Sherlock. The belt comes down again, again, again, and each time Sherlock’s cries become a little quieter, a little weaker, and Mycroft is helpless, _helpless_... He runs forwards, hoping to pull his father and his brother apart, but one muscular arm flings his scrawny fourteen-year-old body to one side. The pain of the impact is nothing compared to the horror of watching Sherlock beaten so severely, and Mycroft swears to himself that he will never, ever allow himself to be so helpless in protecting his brother again...

The huge, mountainous shape in front of him disappears into the fog, and for just a moment Mycroft knows where he is again. “Sherlock!” he tries to call, though the cold has weakened his voice to barely above a whisper. “Sherlock, where are you?”

“My fault,” he hears Sherlock whine, from somewhere very far away. “I’m sorry, I’m so sorry, I didn’t mean for this..."

“Sherlock?” Mycroft begins to crawl forward blindly. “It’s a hallucination, Sherlock. Whatever you’re seeing, _it’s not real_. Can you hear me? Sherlock!”

But it’s no use. He can’t protect his baby brother from this, never has been able to protect him...

“Sherlock! Can you hear me, Sherlock?”

The mist has once again resolved itself into shapes. Sherlock is in his late twenties. He is a pale, skinny, unhealthy looking thing, and would be even if he wasn’t lying on the floor of his cheap, dilapidated flat in North East London, passed out from a cocaine overdose.

“Sherlock!” Mycroft says again, shaking his brother’s shoulder’s desperately. “Sherlock, wake up. Please, little brother...” Yet again, he has failed to protect him. Yet again, the world has brought Sherlock to his knees, and Mycroft should have been there to take the blow for him. “Please... I’ll never let you get hurt again, just wake up, _please_...”

It is a false promise, and Mycroft knows it. They flash before his eyes, time after time after time that he has let Sherlock down, and why does he even bother to try? It would make no difference at all if Mycroft were to lie down here and just let the cold take him, just die right where he is...

As if it could read his thoughts, a figure looms before him out of the fog, black-robed and hooded like Death itself, heaving great, rattling breaths of cold air. Mycroft watches, no longer possessing the strength to move or even to be surprised. The creature brings its face an inch away from his own, and begins to lower its hood...

“EXPECTO PATRONUM!”

A light, blindingly bright. Is this dying? Mycroft wonders vaguely. The light of an afterlife? How unexpected.

 

The hooded figure has turned its attention away from Mycroft, and is looking at the light. Mycroft follows its gaze, and his blurry eyes manage to make out the shape of a four-legged animal. As it comes closer he recognises it as a pure-white dog, a large and fluffy breed that might have been considered cute under any other circumstance. This one looks furious. Teeth bared and eyes wild, it flings itself at the dark creature, giving unearthly, echoing barks. The figure throws itself backwards and swoops away, disappearing into the mist again.

The glowing dog approaches Mycroft. With the enemy gone, it is giving out what he can only describe as an aura of calmness, and despite the cold he feels the first flickering of hope crawl back into him. He reaches out a hand to it weakly. Suddenly the dog turns tail and sprints away again.

But as it disappears, so appears the outline of John Watson.

John is by nature a harmless-looking man, but on their first meeting Mycroft noticed the steel in his eyes. Now all traces of innocence are gone, and it is John the Soldier who stands before him. His weapon is a rather inoffensive piece of wood, which he is brandishing like a magic wand, but his demeanour could not have been more threatening. Rage emanates off him like fire, and he runs forwards with a purpose that propels him almost instantly to Mycroft’s side.

“Mycroft! Are you alright?” John stares at him for a moment, then holds out a hand. “Can you stand up?”

“Yes,” Mycroft says, his voice reedy and cracked. He takes John’s hand and pulls himself to his feet, although his legs shake underneath him. “Yes, I’m fine. What-?”

“Did you see the dog?” John asks urgently.

“Yes, it was – it was huge, John, what was-?”

“Oh, fuck. The Ministry’ll be all over this in hours, fuck.”

If there is a Ministry that deals with glowing animals and unnaturally cold and terrifying fogs, it is not one Mycroft has ever had dealings with. Instead of questioning it, however, he says, “John. Sherlock – Sherlock’s out there somewhere.”

“Shit.” John turns away and hurries out into the mist, and Mycroft somehow forces his legs to follow. John reaches into his pocket as they move, finds a piece of chocolate and presses it into Mycroft’s hands. “Eat.”

Mycroft looks at it. He blinks at it. Eventually he says, slightly pathetically, “But I’m on a _diet_...”

“Fuck your diet. _Eat_ ,” John repeats firmly, and Mycroft does as he is told. He nibbles at the corner and, to his surprise, the cold seems to retreat a little. He takes a larger bite, and is suddenly filled with a warmth and vague happiness he could not have imagined just minutes before.

“John, what’s going on?” he asks again, his voice a little stronger after the chocolate. “Where’s my brother?”

“I’m trying to find him,” John said in frustration. “I can’t see a thing in this fog, though... _Lumos_!”

The end of the twig John is holding starts to glow inexplicably, penetrating just a little further into the gloom. Mycroft stares at it, and then his eyes move to John’s face.

“Don’t ask,” John says, before Mycroft can even open his mouth. “The Prophet’s going to have a field day with this as it is... Sherlock! Sherlock, where are you?”

There is a groan, and John runs towards it. Mycroft loses sight of him again, but can hear his voice, saying “Sherlock! Look at me, Sherlock, it’s OK, it’s over. It’s fine, Sherlock, I’m here...” Mycroft follows that voice, and eventually finds his brother, half-conscious and terrified, crying into John’s front while John repeats comfortingly, “I’m fine, Sherlock, I’m OK...”

_I’m_ fine, Mycroft realises, not _You’re_ fine. It’s only then he makes out the words in Sherlock’s half-strangled sobs.

“John... John... you were dead, John..."

**Author's Note:**

> For those interested, John's Patronus is a Kuchi dog, which is large, fluffy, ferocious, and native to Afghanistan.


End file.
